The bus from the BW does not go directly to the MK. It stops at YC, then BC, then Swan, Dolphin, then the MK. If you then want to go to the GF you then need to take the monorail or boat to it. Same for the Poly. We had to go to the Poly from the BW and we took the MK bus and it took about 45 min to do this in the beginning of May. That was because we only waited 5 min at the BW for the MK bus, it could've been longer. My advice would be to take a cab.
Also at the BW, the AK bus stopped at the Swan, Dolphine, TL, then DtD. It was a real pain(IMHO) if you just wanted to get somewhere to have to share the bus with all those other resorts, especially when you are trying to make a ressie.
Next time we are at the BW we will either rent a car or use a cab to go to the resorts or DtD, or MK and AK.